Mason Stains and Slip

I am looking for some guidelines on coloring slip with Mason Stains.
I use white clay that's left over from trimming, dry it, add water back to it, sieve and add stain color to that.
So far, my colors are working out pretty well using a 90/10 percent clay/stain.
The gray color of the clay makes it's visually hard to know if I'm adding enough stain to the slip until I bisque and then glaze.

Should the wet slip have an intensity of color when mixed or is it sometimes going to be "weak" in coloration?
What is an average percentage of stain to slip?
Are you supposed to add the dry stain to wet slip?
Should I be adding dry stain to dry clay and then add water?

I have been testing but that's a long trial and error process and I know there's potters with answers out there!
Thanks for any words of wisdom.

Your colored slips will darken as you fire so the initial wet color should never look as dark as you eventually want it. Some colors look washed out until they are fired ... then Wham!! So you just have to trust the fact that you have added enough. After bisque firing, wet the piece and that color will be very close to what it will look like at Cone 6.

In pinks, yellows, mauves, light green I add up to 20 - 25% depending on how bright I want the final color.In dark colors like mazerine, brown, forest green ... 8 - 10% will do it.

I mix mine in a blender ... water, clay, stain.

For your own sanity, run some tests ... just lines of color on plain tiles of your clay.Mix a measured batch at the highest concentration, then use a teaspoon to measure one part plain slip to one part saturated, then two parts plain to one part saturated ... this will give you a good idea of how quickly your colors change so you can guage what you like and how much you need.flower_2_med.jpg15.78KB36 downloads

Thanks Chris! This is great information and giving the link to your site was terrific. It was interesting to learn that your slip mix was thick like cookie dough. I thought it was supposed to be thinner like cream and was having trouble getting it to be opaque without a several coats. I am firing to bisque 04 and glaze 06, so do you think this makes a difference in percentages?

I agree with MadMudder that you're a good woman to answer my questions so well. This forum is a very useful place and, although this is my first post, I've gotten plenty of good info from other posters.

Well, thanks for the compliments ... I think of all the potters who answered my questions and passing on info is like thanking them again.

I can't help much with information for firing that low ... My Mason colors all get fired higher, so get brighter through heat work.
If I was firing that low I would probably use Amaco underglazes, since they are nice rich colors at that temp. I open the jars and let them thicken up to yogurt like cream, then use them like slips.

Chris Campbell

Contemporary Fine Colored Porcelain
www.ccpottery.com

TRY ... FAIL ... LEARN ... REPEAT

" ... If a sufficient number of people are different, no one has to be normal"
Fredrick Bachman

Thanks for the advice on trying the underglazes. I have not worked with them either and, since you should try everything once, I may try them next.

I started low firing after going to a conference recently, liked what I saw and wanted to try it. The Mason stains are working very well at this temperature and create nice colors. There are so many things to try with pottery that it makes it very exciting to learn new techniques and be inspired by other potters. This community forum is great.

Recently I observed several items where colored slip was used in the decoration. I have been surfing the internet to gather as much information as I could on making colored slip. I'm finding (if I am correct) that there is actually 2 different ways to use these Mason Stains, with Glazes and with Slip. The glazed process confuses me because I keep reading about not having this and that - such as zinc, etc or it would alter the color. Makes me feel like I need to be a scientist. With the colored slip the one I am actually interested in - seems we just need to mix the clay with the slip at a percentage. There where several questions I am trying to find answers to and would love the help. The first is, can purchased ready made slip be used with these mason stains to make colored slip? Second, when these colored slips are fired are they gloss or matte? Reason I ask about the matte is, I keep reading that it has to match the glaze contents. Am I reading things into my searching that I shouldn't.

Even though this is an old thread, I'm going to add some information here for anyone looking for more details about mixing mason stains to make colored slip.

I've used both Mason Stains mixed with dried porcelain clay to make a slip and Velvet Underglazes as an alternative.

This is my opinion: Unless you need many different colors, I feel mixing your own colored slip is better. The mason stains can be expensive depending on the color, but a little dry powdered mason stain goes a long way. (making them economical to use) I usually only need to apply one coat and it is sufficient. The Velvet underglazes are quite expensive (for me) and take 3 coats to get good coverage. They do provide a nice smooth finish, and you can use them right out of the bottle, no mixing and measuring. However a slip made with Mason Stains can provide almost as smooth of a finish if you get all the little lumps out of it, and with only one coat. If there is a high spot, let it dry completely and use some extra fine sandpaper to smooth it out. (A word of caution, always wear gloves when working with mason stains, and if you sand on it, wear a mask).

I apply my mason stained slip to leather hard clay. After bisque firing, the mason stains (as well as the Velvets) will be matt. I use a zinc free clear gloss glaze, and fire to ^5 - ^6 in an electric kiln. The colors are vibrant.

As others have said, to get the exact color you want you'll have to test. But these are the colors and percentages I use, and that will give you a starting point.

Black 10%

White 20%

Tangerine 5% (fires to a med-orange)

Bermuda Blue/Green 12% (pastel, add a bit more for darker color)

Chartreuse 40%

Dark Turquoise 10% (pastel, add more for darker color)

Vanadium Yellow 12% (golden yellow)

Violet 40%

This is how I mix my mason stains to make colored slip:

I use porcelain clay when I throw, and I save all the "shavings" from when I trim. I let these dry completely, and then grind them (wear a mask!) in a mortar and pestle into a fine powder.

Using a gram scale, I start with 50g of powdered clay. Then add the mason stain according to the percentage. (In this example if 12% is needed, add 6g of stain.) Mix the mason stain into the dried slip until you have a uniform color. Add water, a little (like a teaspoon) at a time, stirring well, better to have it too thick than too thin to start off, you can always add more water at the end. I mix my slips to the consistency of pancake batter. Let it sit overnight. It will have thickened considerably. Stir it again and get it to the consistency you want by adding more water if necessary. Then pour (more like push and scrape) it through an 80 mesh sieve. This makes a small amount which I like because they tend to dry out and get gunky after about a month or two, and that's about how long it takes me to use it up. (except for black and white and I make 100g batches of those). Dried out slips can be re-constituted, with water, but I find this tedious. I keep my mixed slips in small plastic containers with tight fitting lids, and always give it a few sprays of water before putting it away. (I live in a very dry climate)